The present invention relates generally to a system and method for the treatment of disorders of the vasculature. More specifically, the present invention relates to a system and method for treatment of thoracic or abdominal aortic aneurysm and the like, which is a condition manifested by expansion and weakening of the aorta. Prior methods of treating aneurysm have consisted of invasive surgical methods with graft placement within the affected vessel as a reinforcing member of the artery. However, such a procedure requires a surgical cut down to access the vessel, which in turn can result in a catastrophic rupture of the aneurysm due to the decreased external pressure from the surrounding organs and tissues, which are moved during the procedure to gain access to the vessel. Accordingly, surgical procedures can have a high mortality rate due to the possibility of the rupture discussed above in addition to other factors. Such other risk factors for surgical treatment of aortic aneurysms can include poor physical condition of the patient due to blood loss, anuria, and low blood pressure associated with the aortic abdominal aneurysm. An example of a surgical procedure is described in a book entitled Surgical Treatment of Aortic Aneurysms by Denton A. Cooley, M.D., published in 1986 by W. B. Saunders Company.
Due to the inherent risks and complexities of surgical intervention, various attempts have been made to develop alternative methods for deployment of grafts within aortic aneurysms. One such method is the non-invasive technique of percutaneous delivery by a catheter-based system. Such a method is described in Lawrence, Jr. et al. in xe2x80x9cPercutaneous Endovascular Graft: Experimental Evaluationxe2x80x9d, Radiology (May 1987). Lawrence described therein the use of a Gianturco stent as disclosed in U.S. Pat. No. 4,580,568. The stent is used to position a Dacron fabric graft within the vessel. The Dacron graft is compressed within the catheter and then deployed within the vessel to be treated. A similar procedure has also been described by Mirich et al. in xe2x80x9cPercutaneously Placed Endovascular Grafts for Aortic Aneurysms: Feasability Studyxe2x80x9d, Radiology (March 1989). Mirich describes therein a self-expanding metallic structure covered by a nylon fabric, with said structure being anchored by barbs at the proximal and distal ends.
One of the primary deficiencies of the existing percutaneous devices and methods has been that the grafts and the delivery systems used to deliver the grafts are relatively large in profile, often up to 24 French, and stiff in longitudinal bending. The large profile and relatively high bending stiffness of existing delivery systems makes delivery through the vessels of a patient difficult and can pose the risk of dissection or other trauma to the patient""s vessels. In particular, the iliac arteries of a patient are often too narrow or irregular for the passage of existing percutaneous devices. Because of this, non-invasive percutaneous graft delivery for treatment of aortic aneurysm is contraindicated for many patients who would otherwise benefit from it.
What is needed is an endovascular graft and delivery system having a small outer diameter relative to existing systems and high flexibility to facilitate percutaneous delivery in patients who require such treatment. What is also needed is a delivery system for an endovascular graft that is simple, reliable and that can accurately and safely deploy an endovascular graft within a patient""s body, lumen or vessel.
The invention is directed generally to a delivery system for delivery of an expandable intracorporeal device, specifically, an endovascular graft. Embodiments of the invention are directed to percutaneous non-invasive delivery of endovascular grafts which eliminate the need for a surgical cut-down in order to access the afflicted artery or other intracorporeal conduit of the patient being treated. Such a non-invasive delivery system and method result in shorter procedure duration, expedited recovery times and lower risk of complication. The flexible low profile properties of some embodiments of the invention also make percutaneous non-invasive procedures for delivery of endovascular grafts available to patient populations that may not otherwise have such treatment available. For example, patients with small anatomies or particularly tortuous vasculature may be contraindicated for procedures that involve the use of delivery systems that do not have the flexible or low profile characteristics of embodiments of the present invention.
In one embodiment, the delivery system has an elongate shaft with a proximal section and a distal section. The distal section of the elongate shaft includes a portion having an expandable intracorporeal device. An elongate belt support member is disposed adjacent a portion of the expandable intracorporeal device and a belt is secured to the belt support member and circumferentially disposed about the expandable intracorporeal device. The belt member constrains at least a portion of the expandable intracorporeal device. A release member releasably secures the belt in the constraining configuration.
Another embodiment of the invention is directed to a delivery system that has an elongate shaft with a proximal section and a distal section. The distal section of the elongate shaft has an elongate belt support member disposed adjacent a portion of the expandable intracorporeal device. A belt is secured to the belt support member and is circumferentially disposed about the expandable intracorporeal device. The belt has a configuration which constrains the expandable intracorporeal device and a release member releasably secures the belt in the constraining configuration. The belt may constrain any portion of the expandable intracorporeal device, such as a self-expanding portion of the expandable intracorporeal device. A self-expanding portion of the device may include a self-expanding member such as a tubular stent.
In a particular embodiment of the invention, a plurality of belts are secured to various axial positions on the belt support member, are circumferentially disposed about the expandable intracorporeal device and have a configuration which constrains the expandable intracorporeal device. At least one release member releasably secures the belts in the constraining configuration. Each belt can be released by a single separate release member which engages each belt separately, or multiple belts can be released by a single release member. The order in which the belts are released can be determined by the axial position of the belts and the direction of movement of the release member.
Another embodiment of the invention is directed to a delivery system for delivery of a self-expanding endovascular graft with a flexible tubular body portion and at least one self-expanding member secured to an end of the endovascular graft. The delivery system has an elongate shaft having a proximal section and a distal section. The distal section of the elongate shaft has an elongate belt support member disposed within the self-expanding member of the endovascular graft and a belt which is secured to the belt support member adjacent the self-expanding member. The belt is also circumferentially disposed about the self-expanding member and has a configuration which constrains the self-expanding member. A release wire releasably secures ends of the belt in the constraining configuration.
A further embodiment of the invention includes a delivery system for delivery of an endovascular graft with a flexible tubular body portion and a plurality of self-expanding members secured to ends of the endovascular graft. The delivery system has an elongate shaft with a proximal section and a distal section. The distal section of the elongate shaft has an elongate guidewire tube disposed within the endovascular graft in a constrained state. A plurality of shape memory thin wire belts are secured to the guidewire tube respectively adjacent the self-expanding members. The belts are circumferentially disposed about the respective self-expanding members and have a configuration which constrains the respective self-expanding members. A first release wire releasably secures ends of the belts disposed about the self-expanding members at the proximal end of the endovascular graft in a constraining configuration. A second release wire releasably secures ends of the belts disposed about the self-expanding members at a distal end of the endovascular graft in the constraining configuration.
The invention also is directed to a method for deploying an expandable intracorporeal device within a patient""s body. The method includes providing a delivery system for delivery of an expandable intracorporeal device including an elongate shaft having a proximal section and a distal section. The distal section of the elongate shaft has an elongate belt support member disposed adjacent a portion of the expandable intracorporeal device and a belt which is secured to the belt support member. The belt is circumferentially disposed about the expandable intracorporeal device and has a configuration which constrains the expandable intracorporeal device. A release member releasably secures the belt in the constraining configuration.
Next, the distal end of the delivery system is introduced into the patient""s body and advanced to a desired site within the patient""s body. The release member is then activated, releasing the belt from the constraining configuration. Optionally, the delivery system may also have an outer protective sheath disposed about the endovascular graft in a constrained state, the belt in its constraining configuration and at least a portion of the release wire disposed at the belt. In such an embodiment, the method of deployment of an expandable intracorporeal device also includes retraction of the outer protective sheath from the endovascular graft prior to activation of the release member.
In an embodiment of the invention directed to delivery of bifurcated intracorporeal device, an elongate shaft has a proximal section and a distal section. The distal section of the shaft has an elongate primary belt support member and at least one primary belt disposed on the primary belt support member. The primary belt support member is configured to be circumferentially disposed about a bifurcated intracorporeal device and at least partially constrain the device. A primary release member is configured to engage and releasably secure the primary belt in a constraining configuration. At least one elongate secondary belt support member is disposed adjacent the elongate primary belt support member. At least one secondary belt is disposed on the secondary belt support member. This at least one secondary belt is configured to be circumferentially disposed about a bifurcated intracorporeal device and at least partially constrain the device. A secondary release member is configured to engage and releasably secure the secondary belt in a constraining configuration.
In a method for deploying a bifurcated intracorporeal device within a patient""s body, a delivery system for delivery and deployment of a bifurcated intracorporeal device is provided. The delivery system includes an elongate shaft having a proximal section and a distal section. The bifurcated intracorporeal device is disposed on the distal section of the elongate shaft. The distal section of the elongate shaft also includes an elongate primary belt support member and at least one primary belt secured to the primary belt support member. The primary belt is configured to be circumferentially disposed about a bifurcated intracorporeal device and at least partially constrain the device. A primary release member engages and releasably secures the primary belt in the constraining configuration. The distal section of the elongate shaft also includes at least one elongate secondary belt support member disposed adjacent the elongate primary belt support member. At least one secondary belt is secured to the secondary belt support member and is configured to be circumferentially disposed about a bifurcated intracorporeal device to at least partially constrain the device. A secondary release member engages and releasably secures the secondary belt in a constraining configuration.
The distal end of the delivery system is introduced into the patient""s body and advanced to a desired site within the patient""s body. The release members are then activated to release the belts from the constraining configuration and the device is deployed. Thereafter, the delivery system can be removed from the patient""s body. In some embodiments of the invention, the secondary belt support member is detached and removed from the delivery system prior to withdrawal of the delivery system from the patient. In another embodiment, the secondary belt support member is displaced laterally towards the primary belt support member so as to be substantially parallel to the primary belt support member and enable withdrawal of the delivery system through an ipsilateral side of the bifurcated intracorporeal device.